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2016-05-20 13:56:52 -07:00
export class Tree<T> {
/** @internal */
_root: TreeNode<T>;
constructor(root: TreeNode<T>) { this._root = root; }
get root(): T { return this._root.value; }
parent(t: T): T {
const p = this.pathFromRoot(t);
return p.length > 1 ? p[p.length - 2] : null;
}
children(t: T): T[] {
const n = _findNode(t, this._root);
return n ? n.children.map(t => t.value) : null;
}
firstChild(t: T): T {
const n = _findNode(t, this._root);
return n && n.children.length > 0 ? n.children[0].value : null;
}
pathFromRoot(t: T): T[] { return _findPath(t, this._root, []).map(s => s.value); }
contains(tree: Tree<T>): boolean { return _contains(this._root, tree._root); }
}
export function rootNode<T>(tree: Tree<T>): TreeNode<T> {
return tree._root;
}
function _findNode<T>(expected: T, c: TreeNode<T>): TreeNode<T> {
if (expected === c.value) return c;
for (let cc of c.children) {
const r = _findNode(expected, cc);
if (r) return r;
}
return null;
}
function _findPath<T>(expected: T, c: TreeNode<T>, collected: TreeNode<T>[]): TreeNode<T>[] {
collected.push(c);
if (expected === c.value) return collected;
for (let cc of c.children) {
const cloned = collected.slice(0);
const r = _findPath(expected, cc, cloned);
if (r) return r;
}
return null;
}
function _contains<T>(tree: TreeNode<T>, subtree: TreeNode<T>): boolean {
if (tree.value !== subtree.value) return false;
for (let subtreeNode of subtree.children) {
const s = tree.children.filter(child => child.value === subtreeNode.value);
if (s.length === 0) return false;
if (!_contains(s[0], subtreeNode)) return false;
}
return true;
}
export class TreeNode<T> {
constructor(public value: T, public children: TreeNode<T>[]) {}
}